Electric switch



Oct. 13, 1931. T GREENwoQD 1,827,516 Y ELECTRIC SWITCH Filed Deb. 11, 1924 fiver? 2'01:

' the quench the arc.

meme O t. 13,1931

UNITED STATES 'PATENT OFFICE TALMA r. simm woonor ms'r TEMPLETON, massacnnsms, assrcnon, BY mini 'ASSIGNMENTS, TO CONDIT ELEGIBICAL MANUFACTURING CORPORATION, 01

BOSTON, 'MASSACHUBETTS, A. CORPORATION 01 MASSACHUSETTS v ELECTRIC SWITCH Application filed December 11, 1924, Serial Io. 755,853.

This invention relates to electric switches and has as an object the provision of-magnetic means to rotate the circuit-interrupting arc about the separated cooperating contact members of an electric switch, and

through. relatively cool masses of an arcquenching fluid, whereby to assist in extinguishing the arc and interrupting the circuit.

A further object of this invention is generally to improve the construction and op-.

eration of electric switches.

' Fig. 1 is a side elevation of the relatively separable contact members of an electric switch constructed and arranged in accordance with the invention.

Fi 2 is a view similar to Fig. 1 but with xed contact member illustrated in section and with'the contact members separated.

This invention provides relatively separable contact members immersed in a. suitable arc-quenching fluid and arranged to draw an are between them, in combination with means to set up a magnetic field which is so related to the are as to rotate it about the separated contact members and through the body of arcquenching fluid, whereby rapidly to cool and In the specific embodiment of the invention illustrated, the relatively separable con.- tact members are immersed m a body of oil or other arc-quenching fluid 8. The fixed contact or arcin member 10 may be secured to the lower en of a conducting block. 12, which block may be connected electrically with a' switch terminal 14 and. dis osed at the lower-end ofan insulating bus ing 16. The fixed. contact member may be tubular and may be provided with an enlarged upper internal portion, or bowl 18, an inter mediate reduced portion, or throat 20, and a lower expanding portion, or nozzle 22, which nozzle converges smoothly into the throat 20. The lower portion, or nozzle, is adapted to rovide an annular arcing surface about whlch the circuit-interrupting arc is adapted to be rotated magnetically. The upper in-' ternal portion, or bowl, of the fixed contact member may be provided with the internal screw-threads 24 into which the lower and externally screw-threaded portion of the block 12 is adapted removably to be received, whereby to secure the fixed contact member detachably in position.

A primary arcing member, which may be in the form of a conducting button 26, is dis posed within the bowl of the fixed contact member and co-axially thereof, and may be threaded removably into said block 12.

The movable contact or arcing member 28 is supported upon the upper end of a vertically movable switch rod 30. Said contact member is more or less barrel-shaped, or is provided with an enlarged intermediate portion 32 and reduced top and bottom portions,

and the top face 34 thereof is adapted electrically to engage the primary arcing mem ber 26. Said movable contact member is adapted to be moved into and out of the fixed contact member and be free from contact with the inner face thereof during such movements. When the two contact members are in circuit-closing relation, as illustrated in Fig. 1, the enlarged portion of the movable contact member is adapted to be disppsed in the throat of the fixed contact mem- When the contact members are separated under load, the circuit-interrupting arc is adapted to be drawn between the primary arcing member and the tip of the movable contact member and thence pass to the inner wall of the stationary contact member and internally down said contact member to the nozzle. In some position of the contact members, the circuit-interrupting arc may assume a position illustrated in Fig. 2, wherein A represents the arc; in which position the arc is or may be angularly-related to the line of se aration of the two contact members.

n accordance with this invention, magnetic means are provided to set up a magnetic field which acts on the circuit-interrupt--' ing arc in a direction torotate it flbOllt aid contact members, whereby to cause the 8.13 to travel over relatively cold contact surfaces and through fresh masses of'cold arc-quenchin fluid, and become uenched rapidly.

n the specific embodiment of the invention herein set forth, the fixed contact member comprises a part of said-magnetic means. To

this end, said contact member is formed or provided with a spiral slot or groove 36 which extends entirely through the sidewall, from the throat 20 to the internally screwthreaded upper portion thereof, thereby forming a plurality of turns or convolutions 38 of conductor through which the current passes in series from the switch terminal 14 to the arcing face, or nozzle 22, of the contact member. Said convolutions comprise a solenoid disposed in proximity to the circuitinterrupting arc. The magnetic field, set up by said solenoid is approximately in the direction indicated by the arrows B. and passes approximately at right angles through the arc zone and concentrically with the line of separation of the contact members. Inasmuch as the same current traverses the solenoid and the circuit-interrupting arc, a unidirectional driving force is set up on the are which tends to revolve it rapidly about the cold contact members and through the body of cold oil, whereby rapidly to extinguish the arc.

As the movable arcing member is being withdrawn from within the bowl it is apparent that the arc revolves about the inner face of the bowl and downwardly, following the convolutions thereof, whereby the number of convolutions included in the circuit is progressively increased until the arcreaches the nozzle.

The convolutions provide an inherent reactance the value of which is progressively increased as the arc reyolves downwardly within the bowl, whereby gradually to increase the choking effect of the reactance on the arc current.

The rate of rotation of the arc may be relatively high and, inasmuch as. when rotating, the are is cutting a magnetic field, a relatively high counter electro-motive force may be set up which may assist materially in reducing the amount of energy to be interrupted.

The construction may be otherwise modified without departing from the spirit of the invention.

I claim:

1. In an electric switch, the combination of a fixed annular arcing surface. a cooperating annular arcing surface movable within and along the axis of said first annular arcing surface, both arcing surfaces being immersed in oil, and a solenoid disposed approximately along the axis of and comprising a part of said first annular arcing surface to exert its arc-rotating magnetic field transversely of the arc zone between said arcing surfaces.

. 2. A circuit controlling device including an arcing member, and a cooperating arcing member comprising a solenoid which is so disposed with respect to said first arcing member that the electric arc is rotated about and in contact with the convolutions of said solepoid by the magnetic effect of the soleno1 -3. An electric switch having the combination of an arcing member comprising a solenoid one or more of the convolutions of which provide an arcing face, and a. cooperating arcing member arranged approximately in the axis of the solenoid and in the magnetic field thereof.

4. A circuit controlling device including an arcing'member comprising a solenoid, and a cooperating movable arcing member movable into and out of said solenoid.

5. A circuit controlling device including an arcing member comprising a solenoid, and a cooperating arcing member which is movable into and out of said solenoid and which establishes therewith an are that is disposed transversely to the magnetic field of said solenoid.

6. A circuit controlling device including an arcing member of spiral configuration, and a cooperating'arcing member movable in and out of said spiral.

7. A circuit interrupter having the combination of arc-establishing means, other means to which the established arc-is transferred, and means for rotating the arc. in an endless path in engagement with said other means. 4

8. A circuit interrupter having the combination of arc-establishing means, and arcextinguishing means including a plurality of spaced conducting and arc-supporting elements, and arc-rotating means.

9. A circuit interrupter having the combination of arc-establishing means, arc-rotating means adapted to be traversed by the arc current to rotate the arc and normally excluded from the circuit of said are establishing means, and means to transfer the arc to the circuit of said arc-rotating means.

10. A circuit interrupter having the combination of arc-establishing means, and areextinguishing means including an arc-supporting structure and arc-rotating means electrically in series therewith, said arc-rotating means being normally excluded from the circuit of said arc-establishing means and both means being so arranged that the established arc is passed to the action of said areextinguishing means.

11. A circuit interrupter having the combination of arc-establishing means, arc-supporting means to which the established arc is passed, and means to rotate the arc in an endless path in engagement with said arc-supporting means; a

12. The method of extinguishing an arc in a circuit interrupter having arc-establishing means and arc-supporting means, which consists inestablishing the are at said arc-establishing means, transferring the are to said arc-supporting means and rotating the are in engagement with said arc-supporting means. 1

13. A circuit interrupter having the combination of arc-rotating means normally excluded from the interrupter circuit, and means to establish a circuit interrupting arc and to transfer it to the circuit and to theaction of said arc-rotating means.

14.- A circuit interrupter having the combination of apparatus providing spaced conducting and arc-supporting elements and arc rotating means, and means to establish an are independent of said apparatus and to transfer the arc to the action of said apparatus.

15; An electric switch having the combination of separable contact membersbetween bers, and means to rotate the arc in contac with said arc-supporting device. -17 An electnc switch having means pro viding a plurality of closely-spaced conducting elements, separable arcing members arranged to draw an arc in the vicinity of said elements, to which means the arc is adapted to pass, and means to rotate the arc in engagement with said elements; I

18. An arcing member comprising awtubular member having a thick side wall, said member having integral with the lower end thereof an annular arcing face and integral Y with the upper end thereof an internally screw-threaded connecting part, the intermediate portion of said tubular member having a spiral slot extended through its side wall WhlCh forms in said member a plurality of integral spiral convolutions that constitute a solenoid.'

In testimony whereof, I have signed my name to this specification.

TALMA T. GREENWOOD. 

